People who get lots of exercise are molecularly speaking nine years younger than people who don't exercise at all or only get a little or moderate amount. American sports scientists Larry Tucker wrote about this in Preventive Medicine.

Study

This is the third time that we've written about Larry Tucker's telomere project. So far we've written about studies for which Tucker used data gathered in the National Health and Nutrition Examination Survey. Tucker used the data to show that coffee consumption has a positive effect on telomere length [and caffeine doesn't], as does consuming nuts. If you're not sure what telomeres are and why that means you're biologically younger, then these posts provide an explanation.

In the study that this post is about Tucker looked at the relationship between telomere length and the amount of exercise that 5823 men and women aged between 20 and 84 got.

Results
The biggest factor involved in determining the length of the participants' telomeres was, of course, age. Each year, telomere length decreased by 15.6 base pairs.

Another factor was physical exercise. Tucker found no statistically significant differences in the telomere lengths of the participants who had a purely sedentary lifestyle, those who exercised a little and those who got a moderate amount of exercise. But among the participants who exercised a lot - who walked for at least an hour a day or got an equivalent amount of exercise - the telomeres were significantly longer than those of the other participants.

The effect of a lifestyle that includes a relatively large amount of exercise amounts to a molecular rejuvenation effect of 9 years, Tucker estimates.

Conclusion
"Just because you're 40, doesn't mean you're 40 years old biologically," said Tucker in a press release. [sciencedaily.com May 10, 2017] "We all know people that seem younger than their actual age."

"The more physically active we are, the less biological aging takes place in our bodies. If you want to see a real difference in slowing your biological aging, it appears that a little exercise won't cut it. You have to work out regularly at high levels."